* contain will be cached, but {@code getAll} will throw an exception. If the returned map
   * contains extra keys not present in {@code keys} then all returned entries will be cached, but
   * only the entries for {@code keys} will be returned from {@code getAll}.
   *
   * <p>This method should be overridden when bulk retrieval is significantly more efficient than

    forward.invalidateAll();
    verify(mock).invalidateAll();
  }

  public void testSize() {
    when(mock.size()).thenReturn(0L);
    assertEquals(0, forward.size());
  }

  public void testStats() {
    when(mock.stats()).thenReturn(null);
    assertNull(forward.stats());
  }

  public void testAsMap() {
    when(mock.asMap()).thenReturn(null);
    assertNull(forward.asMap());
  }

  public void testCleanUp() {

   * Comparator}. When multiple elements are equivalent according to {@code compare()}, only the
   * first one specified is included. This method iterates over {@code elements} at most once.
   *
   * <p>Despite the method name, this method attempts to avoid actually copying the data when it is

   *
   * <pre>{@code
   * // Falling back to a zero counter in case an exception happens when processing the RPC to fetch
   * // counters.
   * ListenableFuture<Integer> faultTolerantFuture =
   *     fetchCounters().catching(FetchException.class, x -> 0, directExecutor());
   * }</pre>
   *
   * <p>When selecting an executor, note that {@code directExecutor} is dangerous in some cases. See

   * propagating it.
   *
   * <p>While it's not safe in the general case to ignore exceptions that are thrown when closing an
   * I/O resource, it should generally be safe in the case of a resource that's being used only for
   * reading, such as an {@code InputStream}. Unlike with writable resources, there's no chance that
   * a failure that occurs when closing the stream indicates a meaningful problem such as a failure

   * cached value, which will be recalculated when {@code get()} is called on the reserialized
   * instance. The actual memoization does not happen when the underlying delegate throws an
   * exception.
   *
   * <p>When the underlying delegate throws an exception then this memoizing supplier will keep
   * delegating calls until it returns valid data.
   *

     * block, and reference field assignment is atomic, this may save reacquiring the lock when
     * another thread or the worker task has cleared the count and set the state.
     *
     * <p>When {@link #executor} is a directExecutor(), the value written to
     * {@code workerRunningState} will be available synchronously, and behaviour will be
     * deterministic.

 * <strong>Performance</strong>).
 *
 * <p><strong>Cycle Detection</strong>
 *
 * <p>Deadlocks can arise when locks are acquired in an order that forms a cycle. In a simple
 * example involving two locks and two threads, deadlock occurs when one thread acquires Lock A, and
 * then Lock B, while another thread acquires Lock B, and then Lock A:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)
 * Thread2: acquire(LockB) --X acquire(LockA)

      if (upper == POSITIVE_INFINITY) {
        // Return NaN when lower == NEGATIVE_INFINITY and upper == POSITIVE_INFINITY:
        return NaN;
      }
      // Return NEGATIVE_INFINITY when NEGATIVE_INFINITY == lower <= upper < POSITIVE_INFINITY:
      return NEGATIVE_INFINITY;
    }
    if (upper == POSITIVE_INFINITY) {
      // Return POSITIVE_INFINITY when NEGATIVE_INFINITY < lower <= upper == POSITIVE_INFINITY:

   * occur when using {@link CacheBuilder#weakKeys}, {@link CacheBuilder#weakValues}, or {@link
   * CacheBuilder#softValues}.
   */
  COLLECTED {
    @Override
    boolean wasEvicted() {
      return true;
    }
  },

  /**
   * The entry's expiration timestamp has passed. This can occur when using {@link